> In fact, can recallocarray be faster than plain free followed by calloc?
Yes. I think you are missing some nuances. These added functions have fast paths and slow paths. freezero() isn't just a bzero, it also has munmap() sequences. You are adding forced bzero or munmap() in circumstances where previously a malloc implementation could keep the freed'd memory in a cache for reuse. I find it hard to read your diff as convert other than "convert all free operations to freezero", or always pay the cost no matter what. You could compare make build times. I suspect this will slightly exceed the noise floor.
